The induction of lipid peroxidation in the eye pigment epithelium of pigmented rabbits by the Fe2+ + ascorbate and xanthine--xanthine oxidase systems did not result in accumulation of malonic dialdehyde. In albino rabbits the lipid peroxidation of the non-pigmented pigment epithelium and retina occurred at a high rate under the same conditions. The rate of lipid peroxidation also showed an increase after removal of melanoprotein granules from the pigmented pigment epithelium. The latter inhibited the rate of lipid peroxidation in the eye retina. In albino animals the rate of lipid peroxidation in a mixture of the tow tissues (i.e. pigment epithelium and retina) is almost 4 times that in the pigmented animals. Consequently, the pigmented pigment epithelium of the eye is much more resistant to the effect of prooxidant systems as compared to the non-pigmented one. It is assumed that one of the main functions of the melanoprotein granules in the eye pigment epithelium cells is their protective effect.